Vehicle fuel economy may be increased by stopping an engine of a vehicle when operating conditions indicate little or no engine torque is desired. For example, it may be desirable to stop an engine of a vehicle when the vehicle is stopped for a traffic light or while the vehicle is stopped and waiting to pick up a passenger. By stopping the engine fuel consumption may be reduced as compared to continuing to operate the engine at idle. The engine may be automatically restarted when the driver of the vehicle releases a brake pedal or depresses an accelerator pedal. However, vehicle launch or acceleration from stop may not provide a desired response during some conditions because the engine may be loaded via peripheral systems that demand power upon engine restart.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for improving vehicle launch (e.g., acceleration from a vehicle speed less than a threshold speed). One example of the present description provides for a vehicle launch control method, comprising: adjusting a load of an alternator applied to an engine in response to a steering input and an engine torque request.
Thus, vehicle launch may be improved by considering vehicle steering input and engine torque request. In particular, when a steering angle input or a steering torque is at a higher level, power supplied by the engine to an electric steering system can be increased so that the vehicle can start to turn more quickly. On the other hand, if an engine torque request is at a higher level, additional engine torque may be provided to vehicle wheels to improve vehicle acceleration. Further, when the engine torque demand and the steering angle are at medium levels, engine power may be supplied to vehicle wheels and the electric steering system in response to weighted engine torque request and steering input.
The present description may provide several advantages. Specifically, the approach may improve vehicle launch so that a driver experiences smoother engine torque during vehicle acceleration. In addition, the approach may improve alternator field control during automatic engine starts. Further, the approach may provide improved engine torque arbitration and engine speed control for vehicles with electric steering systems.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.